Organic light emitting diode display device and method of manufacturing the same

ABSTRACT

An organic light emitting diode (OLED) display device and a method of manufacturing the same is disclosed. In one embodiment, the OLED device includes a substrate; a display unit formed on a display area of the substrate; and an encapsulating film covering i) the display unit and ii) a non-display area surrounding the display area, wherein the density and thickness of the encapsulating film increase in a direction from a center portion of the encapsulating film to an edge portion of the encapsulating film.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2009-0122533, filed on Dec. 10, 2009, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

1. Field

The present invention relates to a an organic light emitting diode(OLED) display device and a method of manufacturing the OLED displaydevice, and more particularly, to an OLED display device improving aside waterproof property and a method of manufacturing the OLED displaydevice.

2. Description of the Related Technology

An organic light emitting diode (OLED) includes an organic lightemitting layer interposed two electrodes. The OLED is self-emissive, andmay be used in a variety of applications, for example, as a thin andbendable display.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

One aspect of the present invention is a film encapsulating structureand a deposition method to improve a side waterproof property of anorganic light emitting diode (OLED) display device.

Another aspect is an OLED display device including a substrate, adisplay unit formed on the substrate, and an encapsulating film coveringthe display unit and a non-display area around the display unit, adensity and a thickness of the encapsulating film increasing in adirection from a center portion of the encapsulating film to an edgeportion of the encapsulating film.

The encapsulating film may be formed by a temperature gradient formed onthe substrate. The temperature gradient may be formed by heating thenon-light emitting area using a mask including a hot wire. Theencapsulating film may be formed of one or more layers of one of aninorganic film and an organic film, or formed by alternating theinorganic film and the organic film.

The inorganic film may include one or more materials selected from amongSiNx, SiOx, AlOx, SiCxNy, SiOxNy, amorphous carbon, InOx, and YbOx. Theencapsulating film may be formed by one selected from among a sputter, athermal evaporator, chemical vapor deposition (CVD), plasma enhancedchemical vapor deposition (PECVD), ion beam assisted deposition (IBAD),and atomic layer deposition (ALD).

Another aspect is a method of manufacturing an OLED display device, themethod including providing a substrate, forming a display unit on thesubstrate, and forming an encapsulating film covering the display unitand a non-display area around the display unit, a density and athickness of the encapsulating film increasing in a direction from acenter portion of the encapsulating film to an edge portion of theencapsulating film.

The forming of the encapsulating film may include forming a temperaturegradient on the substrate and applying an encapsulating film material tothe substrate where the temperature gradient is formed. The forming ofthe temperature gradient may include placing a mask comprising a hotwire on the substrate and heating the non-light emitting area by heatingthe hot wire.

An opening of the mask may have a size to cover the display unit and apart of the non-light emitting area. The forming of the encapsulatingfilm may include stacking one of an inorganic layer and an organic layerinto one or more layers or alternately stacking the inorganic layer andthe organic layer.

Another aspect is an organic light emitting diode (OLED) display devicecomprising: a substrate; a display unit formed on a display area of thesubstrate; and an encapsulating film covering i) the display unit andii) a non-display area surrounding the display area, wherein the densityand thickness of the encapsulating film increase in a direction from acenter portion of the encapsulating film to an edge portion of theencapsulating film.

In the above device, the density and thickness of the encapsulating filmin the non-display area are greater than that of the encapsulating filmin the display area. In the above device, the density and thickness ofthe encapsulating film increase significantly in the border regionbetween the display area and non-display area. In the above device, theencapsulating film is formed of at least one of an inorganic film and anorganic film, or formed by alternating the inorganic film and theorganic film. In the above device, the inorganic film is formed of atleast one of the following: SiNx, SiOx, AlOx, SiCxNy, SiOxNy, amorphouscarbon, InOx, and YbOx. In the above device, the encapsulating filmcomprises at least three layers which alternate an inorganic layer andan organic layer.

Another aspect is a method of manufacturing an organic light emittingdiode (OLED) display device, the method comprising: providing asubstrate; forming a display unit on a display area of the substrate;and forming an encapsulating film so as to cover i) the display unit andii) a non-display area surrounding the display area, wherein the densityand thickness of the encapsulating film increase in a direction from acenter portion of the encapsulating film to an edge portion of theencapsulating film.

In the above method, the forming of the encapsulating film comprises:forming a temperature gradient on the substrate; and applying anencapsulating film material to the substrate where the temperaturegradient is formed. In the above method, the forming of the temperaturegradient comprises: placing a mask comprising a hot wire on thesubstrate; and heating the hot wire so as to heat the non-display area.

In the above method, a plurality of openings are defined in the mask,wherein at least one of the openings has a size to cover the displayunit and a portion of the non-display area. In the above method, theforming of the encapsulating film comprises: stacking at least one of aninorganic layer and an organic layer. In the above method, the formingof the encapsulating film comprises alternately stacking an inorganiclayer and an organic layer. In the above method, the inorganic layer isformed of at least one of the following: SiNx, SiOx, AlOx, SiCxNy,SiOxNy, amorphous carbon, InOx, and YbOx. In the above method, theencapsulating film is formed by at least one of the following: asputter, a thermal evaporator, chemical vapor deposition (CVD), plasmaenhanced chemical vapor deposition (PECVD), ion beam assisted deposition(IBAD), and atomic layer deposition (ALD).

Another aspect is an organic light emitting diode (OLED) display devicecomprising: a substrate; a display area in which at least one OLED isformed; a non-display area surrounding the display area; and anencapsulating film substantially completely covering the display areaand covering at least part of the non-display area, wherein at least oneof the density and thickness of the encapsulating film in the coverednon-display area is greater than that of the encapsulating film in thedisplay area.

In the above device, at least one of the density and thickness of theencapsulating film increases in a direction from a center portion of theencapsulating film to an edge portion of the encapsulating film, andwherein a majority of the edge portion is formed in the coverednon-display area. In the above method, the thickness of theencapsulating film rapidly increases in the border region between thedisplay area and non-display area. In the above method, theencapsulating film comprises a plurality of layers. In the above method,the plurality of layers comprise at least one inorganic layer and atleas one organic layer. In the above method, the plurality of layersinclude at least three layers which alternate an inorganic layer and anorganic layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plane view schematically illustrating an organic lightemitting diode (OLED) display device according to an embodiment of thepresent invention.

FIG. 2 is a cross-sectional view taken along a line A-A′ of FIG. 1.

FIG. 3 is a partial-enlarged cross-sectional view of a display unitshown in FIG. 1.

FIG. 4A is a view for schematically explaining a process of formingdisplay units in a process of forming an encapsulating film on asubstrate according to an embodiment of the present invention.

FIG. 4B is a cross-sectional view taken along a line B-B′ of FIG. 1.

FIG. 5 is a view for schematically explaining a process of forming anencapsulating film on a substrate where display units are formedaccording to an embodiment of the present invention.

FIGS. 6 and 7 schematically illustrate examples of a mask that can beused in a process of forming an encapsulating film.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

An OLED is generally prone to a sharp degradation in performance afterbeing exposed to moisture and oxygen introduced from an ambientenvironment. In this context, the formed OLED is sealed using a can or aglass substrate. Generally, a polymer material such as UV- orheat-curable epoxy or acryl is used for a sealant. However, due to thelow waterproof performance of the polymer material, somecharacteristics, such as luminance, of the OLED degrade under theinfluence of moisture and oxygen introduced to the OLED over time,reducing the lifespan of the OLED. To solve this problem, a moistureabsorbent is provided in a display device so that any moisture that istransferred past the sealant does not affect the OLED. This scheme,however, makes a manufacturing process complex and increases the weightand volume of the display device.

To address this problem, a film encapsulating technique has beenproposed which encapsulates a display device by covering it with aprotective film. Since a film encapsulating material used in the filmencapsulating technique is directly related to the lifespan of an OLED,moisture permeability, adhesion with OLED materials, and thermalexpansion coefficient relative to temperature need to be adjustedproperly. In particular, moisture permeability exerts a significantinfluence on the lifespan of the OLED and thus is considered animportant factor. Moisture permeation through the film encapsulatingmaterial includes permeation in substantially perpendicular to a filmsurface and side permeation through a device cross section, that is, anon-light emitting region.

A conventional film encapsulating material can effectively preventpermeation of moisture or oxygen in substantially perpendicular to asubstrate, but the permeation occurs along an interface of anencapsulating film from the end of the encapsulating film insubstantially parallel to the substrate.

Hereinafter, an exemplary embodiment of the present invention will bedescribed in detail with reference to the accompanying drawings.Throughout the drawings, the thicknesses of layers or regions may beexaggerated for clarity and like reference numerals refer to likeelements. When a portion “includes” a component, this means that othercomponents are not excluded but can be further included unless otherwisespecifically described.

FIG. 1 is a plane view schematically illustrating an organic lightemitting diode (OLED) display device according to an embodiment of thepresent invention, FIG. 2 is a cross-sectional view taken along a lineA-A′ of FIG. 1, and FIG. 3 is a partial-enlarged cross-sectional view ofa display unit shown in FIG. 1.

Referring to FIGS. 1 and 2, an OLED display device 100 includes asubstrate 120 and an encapsulating film 200 which covers a display unit140 provided on the substrate 120. The substrate 120 may be atransparent glass substrate having, for example, SiO₂ as its maincomponent, or may use various materials such as plastic or metal. Thedisplay unit 140 provided on the substrate 120 may include an organicthin film transistor (OTFT) layer 300 a and a pixel unit 300 b. On a topsurface of the substrate 120 may be formed an insulating layer 312, suchas a barrier layer and/or a buffer layer, for preventing the spread ofimpurity ions and the permeation of moisture or external air and forplanarizing the surface.

A TFT 320 is formed on the insulating layer 312 as a driving circuit. Inthe current embodiment, the TFT 320 is illustrated as being of a topgate type by way of example. However, the TFT 320 may be of anothertype. An active layer 321 of the TFT 320 may be formed of asemiconductor material on the insulating layer 312, and a gateinsulating layer 313 is formed to cover the active layer 321. The activelayer 321 may be formed of an inorganic semiconductor material such assilicon or poly silicon, or an organic semiconductor material, andincludes a source region, a drain region, and a channel regiontherebetween.

A gate electrode 322 is provided on the gate insulating layer 313, andan interlayer insulating film 314 is formed to cover the gate electrode322. Source/drain electrodes 323 are provided on the interlayerinsulating film 314, and a planarizing film 315 is provided to cover thesource/drain electrodes 323. However, the TFT 320 is not limited to theabove-described stack structure and may have various structures. Forexample, some of the above elements may be omitted, additional elementsbeing added, or the stacking order may change depending on theembodiment. This applies to other disclosed embodiments.

On the planarizing film 315 is formed an electrode of an OLED, a firstelectrode 331 which is electrically connected to at least one of thesource and drain electrodes 323 through a contact hole 330. A secondOLED electrode 333 is provided on the first electrode 331 to face thefirst electrode 331. The first electrode 331 may function as an anodeelectrode, and the second electrode 333 may function as a cathodeelectrode. However, the polarities of the first electrode 331 and thesecond electrode 333 may be interchanged with each other.

The first electrode 331 may be a transparent electrode or a reflectiveelectrode. In case of being a transparent electrode, the first electrode331 may include indium tin oxide (ITO), indium zinc oxide (IZO), zincoxide (ZnO), or indium oxide (In₂O₃); in case of being a reflectiveelectrode, the first electrode 331 may include a reflective film formedof, for example, Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or acombination thereof, and a transparent film formed of, for example, ITO,IZO, ZnO, or In₂O₃. The second electrode 333 may also be a transparentelectrode or a reflective electrode. In case of being a transparentelectrode, the second electrode 333 may include a film formed bydepositing, for example, Li, Ca, LiF/Ca, LiF/Al, Al, Mg, or acombination thereof toward an intermediate layer, and an auxiliaryelectrode or bus electrode line formed of a transparent conductivematerial, such as ITO, IZO, ZnO, or In₂O₃ on the film. In case of beinga reflective electrode, the second electrode 333 may be formed of, forexample, Li, Ca, LiF/Ca, LiF/Al, Al, Mg, and a combination thereof.

When the substrate 120 includes the TFT 320 as mentioned above, thefirst electrode 331 patterned for each sub-pixel is electricallyconnected to the TFT 320 for each sub-pixel. In this case, the secondelectrode 333 may be formed as a common electrode connected to allsub-pixels. If the substrate 120 does not include the TFT 320 for eachsub-pixel, the first electrode 330 and the second electrode 333 may bepatterned as a stripe to intersect each other, thus being driven in apassive matrix manner.

An organic film layer 332 is interposed between the first electrode 331and the second electrode 333. The organic film layer 332 may be formedof a low-molecular or high-molecular organic material. When using alow-molecular organic material, the organic film layer 332 may be formedby stacking a hole injection layer (HIL), a hole transport layer (HTL),an emission layer (EML), an electron transport layer (ETL), or anelectron injection layer (EIL) alone or in combination thereof. Variousorganic materials for such a purpose can be used, including, but notlimited to, copper phthalocyanine (CuPc), N, N′-Di(naphthalene -1-yl)-N,N′-diphenyl-benzidine (NPB), tris-8-hydroxyquinoline aluminum (Alq3),and the like. These low-molecular organic materials may be produced byvapor deposition using masks. When using a high-molecular organicmaterial, the organic film layer 332 may include an HTL and an EML, inwhich polyethylenedioxythiophene (PEDOT) is used for the HTL and ahigh-molecular organic material, such as of a poly-phenylenevinylene(PPV) family and a polyfluorene family, is used as the EML.

An encapsulating film 200 is provided on the display unit 140 to coverthe display unit 140. As mentioned previously, an OLED of the displayunit 140 is prone to degradation by an external factor such as moistureor oxygen, and thus the encapsulating film 200 prevents permeation ofoxygen or moisture into the display unit 140. The encapsulating film 200may be formed of one or more layers of one of an inorganic layer and anorganic layer, or formed by alternating the inorganic layer and theorganic layer. Although a multi-layered film including three layers 200a, 200 b, and 200 c is shown in FIG. 2, the encapsulating film 200 maybe formed properly according to an optimal film thickness, for example,one layer, or three or more layers.

The inorganic film may include, but not limited to, SiNx, SiOx, AlOx,SiCxNy, SiOxNy, amorphous carbon, InOx, YbOx, and the like. The organicfilm may include, but not limited to, parylene(poly-p-xylylene) (PPX),poly-2-chloro-p-zylylene (PCPX), poly[2-methoxy-r-(2′ethyhexylloxy)-1,4-phenylene vinylene], and the like. When an organiclight emitting display is of a top emission type, the inorganic film andthe organic film may be made of a material having high transparency.

The encapsulating film 200 may be formed using a sputter, a thermalevaporator, chemical vapor deposition (CVD), plasma enhanced chemicalvapor deposition (PECVD), ion beam assisted deposition (IBAD), atomiclayer deposition (ALD), or the like.

The encapsulating film 200 covers the display unit 140, which is adisplay area (DA), and some parts of a non-display area (NDA) around thedisplay unit 140. In one embodiment, as shown in FIG. 2, theencapsulating film 200 is formed such that its thickness and densityincrease in a direction from its center portion toward its edge portion.In another embodiment, at least one of the thickness and density of theencapsulating film 200 increases in a direction from its center portiontoward its edge portion. In another embodiment, at least one of thethickness and density of the encapsulating film 200 is greater in anedge portion thereof than a non-edge portion (including center portion).

Generally, by deposition, a thin film having uniform thickness andcharacteristics can be obtained. Variable which much affect moisturepermeation to the thin film are the density, thickness, and adhesivestrength of the thin film. Even if moisture coming substantiallyperpendicularly to the DA can be blocked, moisture introduced from aside may not be blocked. Therefore, in at least one embodiment, theencapsulating film 200 is formed such that its density and thicknessincrease in the direction from its center portion toward its edgeportion.

A deposition rate varies with a temperature of a substrate, and thedeposition rate increases as the temperature of the substrate increases.Accordingly, in one embodiment, to make density and thickness differentfor different areas of the encapsulating film 200, when the layers 200a, 200 b, and 200 c of the encapsulating film 200 are stacked, differentsubstrate temperatures are set for the DA of the substrate 120 where thedisplay unit 140 is positioned and the NDA around the display unit 140.Therefore, a temperature gradient is formed across the substrate 120such that the substrate temperature of the NDA is higher than that ofthe DA. To form the temperature gradient on the substrate 120, oneembodiment of the present invention may include a heater in a mask usedto stack an encapsulating film material. The mask will be laterdescribed in more detail.

Generally, an encapsulating film forming process is performed afterformation of an OLED. Consequently, a substrate temperature of a DAwhere the OLED is formed is maintained at a temperature being set not tochange the physical properties of organic materials, and a substratetemperature of an NDA is set higher than that of the DA, such that thethickness and density of an encapsulating film formed in the NDA arelarger than those of the encapsulating film formed in the DA.

The temperature and temperature gradient for the substrate 120 maychange with the entire thickness, materials, and deposition method ofthe encapsulating film 200, and a density difference and a thicknessdifference between the center portion and the edge portion of theencapsulating film 200 may differ with the temperature gradient.

The temperature gradient of the substrate 120 is formed each time eachlayer of the encapsulating film 200 is deposited, and thus the densityand thickness of the edge portion of the encapsulating film 200 arelarger than those of the center portion of the encapsulating film 200(or non-edge portion including the center portion), thereby effectivelyreducing an influence of permeation of moisture through a sideinterface.

FIG. 4A is a view for schematically explaining a process of forming adisplay unit in a process of forming an encapsulating film on asubstrate according to an embodiment of the present invention, and FIG.4B is a cross-sectional view taken along a line B-B′ of FIG. 4A.

Referring to FIGS. 4A and 4B, a plurality of panel regions are providedon a substrate 420 and a plurality of display units 440 are formed toinclude OLEDs in the respective panel regions. Each of the display units440 includes a plurality of pixels, each of which includes at least oneOLED. Each OLED may be classified into an active matrix (AM) OLED and apassive matrix (PM) OLED according to whether light emission thereof iscontrolled using a TFT electrically connected to the OLED. The OLEDdisplay device according to the current embodiment can be applied toboth an AM OLED and a PM OLED. Although six panel regions are providedon the substrate 420 in FIG. 4A, the number of panel regions is notlimited to six. After the plurality of display units 440 are formedspaced apart from each other on the substrate 420, an encapsulating filmis formed to cover the display units 440.

FIG. 5 is a view for schematically explaining a process of forming anencapsulating film on a substrate where display units are formedaccording to an embodiment of the present invention. FIGS. 6 and 7schematically illustrate examples of a mask that can be used in aprocess of forming an encapsulating film.

Referring to FIG. 5, a mask 500 is placed on the substrate 420 where thedisplay units 440 are formed. The mask 500 is positioned such that itsopenings reside over the display units 440 and vicinities thereof andits shielding portion resides between the display units 440 on thesubstrate 420.

After the mask 500 is aligned on the substrate 420, a material forforming an encapsulating film, or an encapsulating film material, isdeposited in a direction from a deposition source as indicated by arrowsshown in FIG. 5. The encapsulating film material may be an inorganicmaterial including, but not limited to, SiNx, SiOx, AlOx, SiCxNy,SiOxNy, amorphous carbon, InOx, YbOx, and the like, and may additionallyinclude an organic material such as resin. The encapsulating filmmaterial may be an organic material including, but not limited to,parylene(poly-p-xylylene) (PPX), poly-2-chloro-p-zylylene (PCPX),poly[2-methoxy-r-(2′ ethyhexylloxy)-1,4-phenylene vinylene], and thelike. When the encapsulating film has an inorganic film or amulti-layered structure where an inorganic film and an organic film arealternated, the mask 500 is aligned every film formation for deposition.

Referring to FIGS. 6 and 7, the mask 500 includes a plurality ofopenings 510 corresponding to the display units 440 and vicinitiesthereof and a shielding portion between the openings 510. A depositionmaterial may be deposited on the substrate 420 through the openings 510.In one embodiment, each opening 510 or at least one opening is formed tohave a size larger than that of each display unit 440 to cover eachdisplay unit 440 and some parts of an NDA around the display unit 440.Therefore, the encapsulating film material may be deposited across thedisplay units 440, which are DAs, and some parts of NDAs around thedisplay units 440.

When a thin film is formed by vapor deposition, the thickness andcharacteristics of the film become uniform across the entire area beforedeposited. Even when the same material is used across the entire area ofthe film, a deposition rate and a film density show much differenceaccording to a substrate temperature. Therefore, to perform depositionsuch that film characteristics, as a deposition variable, differ withregions, a mask used in deposition includes a heater in one embodimentof the present invention.

The mask 500 includes a heater, e.g., a hot wire 550, in the shieldingportion thereof, that is, between the openings 510 and outside theopenings 510. One hot wire 550 may be provided between the openings 510as shown in FIG. 6, or one or more hot wires 550, for example, two hotwires 550 may be provided between the openings 510 as shown in FIG. 7.The hot wire 550 may be positioned adjacent to the outline of theopening 510 to heat an NDA of the substrate 420.

If the hot wire 550 of the mask 500 is heated during deposition of theencapsulating film material, a portion of the substrate 420, whichcontacts or is adjacent to the mask 500 including the hot wire 550, isheated. Therefore, on the substrate 420 may be formed a temperaturegradient where temperature increases in a direction from a center potionof the display unit 440 to an edge portion of the display unit 440.Since higher substrate temperature means higher deposition rate, adeposition rate around the outline of the opening 510 is higher thanthat in the center of the opening 510 because a substrate temperaturearound the outline of the opening 510 is higher than that in the centerof the opening 510. As a result, the encapsulating film may have largerthickness and density in the edge portion than those in the centerportion (or non-edge portion including the center portion).

The temperature and temperature gradient for each area of the substrate420 may be set differently according to the entire thickness, materials,and deposition method of the encapsulating film. For example, in case ofusing PECVD for formation of the encapsulating film, a substratetemperature of a DA where the display unit 440 is positioned may bemaintained below about 100° C., and a substrate temperature of an NDAmay be maintained at about 140° C., which is higher than that of the DA,by heating the hot wire 550 of the mask 500. Within a range which doesnot affect an organic device of a DA, the substrate temperature of theNDA heated by the hot wire 550 of the mask 500 may be set higher thanabout 140° C.

The encapsulating film may be formed of at least one of an inorganiclayer and an organic layer, or formed by alternating the inorganic layerand the organic layer. When the encapsulating film has a multi-layeredstructure, a bottom layer, and subsequent layers are sequentially formedin the aforementioned manner. A temperature being set on the substrate420 and a temperature gradient formed on the substrate 420 may differwith a material used in each layer, and a density difference and athickness difference between a center portion and an edge portion of theformed encapsulating film may also vary with the temperature gradient.

As described above, the encapsulating film according to at least oneembodiment of the present invention is formed such that its density andthickness increase in a direction from its center portion to its edgeportion, thereby effectively preventing permeation of moisture or oxygenthrough a side and thus prolonging the lifespan of an OLED displaydevice.

While the present invention has been particularly shown and describedwith reference to an exemplary embodiment thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

1. An organic light emitting diode (OLED) display device comprising: asubstrate; a display unit formed on a display area of the substrate; andan encapsulating film covering i) the display unit and ii) a non-displayarea surrounding the display area, wherein the density and thickness ofthe encapsulating film increase in a direction from a center portion ofthe encapsulating film to an edge portion of the encapsulating film. 2.The OLED display device of claim 1, wherein the density and thickness ofthe encapsulating film in the non-display area are greater than that ofthe encapsulating film in the display area.
 3. The OLED display deviceof claim 1, wherein the density and thickness of the encapsulating filmincrease significantly in the border region between the display area andnon-display area.
 4. The OLED display device of claim 1, wherein theencapsulating film is formed of at least one of an inorganic film and anorganic film, or formed by alternating the inorganic film and theorganic film.
 5. The OLED display device of claim 4, wherein theinorganic film is formed of at least one of the following: SiNx, SiOx,AlOx, SiCxNy, SiOxNy, amorphous carbon, InOx, and YbOx.
 6. The OLEDdisplay device of claim 1, wherein the encapsulating film comprises atleast three layers which alternate an inorganic layer and an organiclayer.
 7. A method of manufacturing an organic light emitting diode(OLED) display device, the method comprising: providing a substrate;forming a display unit on a display area of the substrate; and formingan encapsulating film so as to cover i) the display unit and ii) anon-display area surrounding the display area, wherein the density andthickness of the encapsulating film increase in a direction from acenter portion of the encapsulating film to an edge portion of theencapsulating film.
 8. The method of claim 7, wherein the forming of theencapsulating film comprises: forming a temperature gradient on thesubstrate; and applying an encapsulating film material to the substratewhere the temperature gradient is formed.
 9. The method of claim 8,wherein the forming of the temperature gradient comprises: placing amask comprising a hot wire on the substrate; and heating the hot wire soas to heat the non-display area.
 10. The method of claim 9, wherein aplurality of openings are defined in the mask, wherein at least one ofthe openings has a size to cover the display unit and a portion of thenon-display area.
 11. The method of claim 7, wherein the forming of theencapsulating film comprises: stacking at least one of an inorganiclayer and an organic layer.
 12. The method of claim 7, wherein theforming of the encapsulating film comprises alternately stacking aninorganic layer and an organic layer.
 13. The method of claim 7, whereinthe inorganic layer is formed of at least one of the following: SiNx,SiOx, AlOx, SiCxNy, SiOxNy, amorphous carbon, InOx, and YbOx.
 14. Themethod of claim 7, wherein the encapsulating film is formed by at leastone of the following: a sputter, a thermal evaporator, chemical vapordeposition (CVD), plasma enhanced chemical vapor deposition (PECVD), ionbeam assisted deposition (IBAD), and atomic layer deposition (ALD). 15.An organic light emitting diode (OLED) display device comprising: asubstrate; a display area in which at least one OLED is formed; anon-display area surrounding the display area; and an encapsulating filmsubstantially completely covering the display area and covering at leastpart of the non-display area, wherein at least one of the density andthickness of the encapsulating film in the covered non-display area isgreater than that of the encapsulating film in the display area.
 16. TheOLED display device of claim 15, wherein at least one of the density andthickness of the encapsulating film increases in a direction from acenter portion of the encapsulating film to an edge portion of theencapsulating film, and wherein a majority of the edge portion is formedin the covered non-display area.
 17. The OLED display device of claim15, wherein the thickness of the encapsulating film rapidly increases inthe border region between the display area and non-display area.
 18. TheOLED display device of claim 15, wherein the encapsulating filmcomprises a plurality of layers.
 19. The OLED display device of claim18, wherein the plurality of layers comprise at least one inorganiclayer and at least one organic layer.
 20. The OLED display device ofclaim 18, wherein the plurality of layers include at least three layerswhich alternate an inorganic layer and an organic layer.